Today: Partly sunny with scattered showers. Highs 79 to 84 near the shore to 65 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers. Lows 62 to 69 near the shore to around 55 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.
Tuesday: Partly sunny with scattered showers. Highs 79 to 85 near the shore to 65 to 71 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.
Kona
Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 81 to 87 near the shore to around 69 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 72 near the shore to 50 to 55 near 5000 feet. Light winds. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Tuesday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 80 to 86 near the shore to around 69 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.
Waimea
Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 80 near the shore to 70 to 79 near 3000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.
Tonight: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows 63 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.
Tuesday: Breezy. Partly sunny with scattered showers. Highs around 80 near the shore to 71 to 78 near 3000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.
Kohala
Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 80 near the shore to 70 to 79 near 3000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows 63 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.
Tuesday: Breezy. Partly sunny with scattered showers. Highs around 80 near the shore to 71 to 78 near 3000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.
South Big Island
Today: Breezy. Mostly sunny with isolated showers. Highs around 83 near the shore to around 65 near 5000 feet. East winds 10 to 25 mph decreasing to up to 25 mph in the afternoon. Chance of rain 20 percent.
Tonight: Mostly clear. Breezy. Isolated showers in the evening. Lows around 73 near the shore to around 51 near 5000 feet. Northeast winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 20 percent.
Tuesday: Breezy. Mostly sunny with isolated showers. Highs around 83 near the shore to around 66 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.
Puna
ARTICLE CONTINUES BELOW AD
Today: Partly sunny with scattered showers. Highs 79 to 84 near the shore to 65 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers. Lows 62 to 69 near the shore to around 55 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.
Tuesday: Partly sunny with scattered showers. Highs 79 to 85 near the shore to 65 to 71 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.
Waikoloa
Today: Sunny and breezy. Isolated showers in the afternoon. Highs 81 to 89 near the shore to 65 to 73 above 4000 feet. North winds up to 20 mph. Chance of rain 20 percent.
Tonight: Mostly clear. Isolated showers in the evening. Lows around 72 near the shore to 50 to 55 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.
Tuesday: Mostly sunny with isolated showers. Highs 81 to 88 near the shore to 65 to 73 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.
Detailed Forecast
Synopsis
High pressure far northeast of the islands will keep moderate to breezy trade winds in place through much of the week with only minor fluctuations in strength from day to day. Showers will generally favor windward and mauka areas. Developing troughing aloft coinciding with occasional increases in low-level moisture will bring a trend toward wetter trade wind weather tonight into Tuesday, and again later in the week through the weekend.
Discussion
Satellite and radar imagery show an increase in low clouds and showers across most of the windward waters early this morning, though the showers remain light at this time. A tenth of an inch of rain or less has fallen at a few locations in northern Oahu, windward Kauai, and the Puna district of the Big Island. Surface high pressure remains centered far northeast of Hawaii, with a ridge axis extending westward to the north of the state. This high continues to producing locally breezy easterly trade wind flow across the islands. Water vapor imagery also shows a slight weakness in the upper ridge just west of Kauai and extending southeast along the rest of the leeward waters. According to the 12Z soundings at Lihue and Hilo, this weakness is allowing the trade wind inversion to lift a bit this morning, likely aiding the slight increase in showers.
The area of high pressure northeast of the island chain is expected to strengthen slightly today, yet remain nearly stationary through much of the coming week. This will keep moderate to locally breezy trades over the islands for the next several days with only minor speed fluctuations.
The GFS and ECMWF both continue to show the development of a weak upper-level trough in the vicinity of the state over the next day or two. This trough will meander over and around the islands with varying strength over the next several days. As this occurs, the trade wind inversion will gradually erode. Tonight, low-level moisture from an old frontal boundary east of the state will approach the islands on the trade wind flow. The combination of this additional moisture and the trough aloft is expected to bring an increase in both trade shower coverage and intensity tonight into Tuesday. Both global models indicate the trough deepening into a closed upper low around Wednesday night and lingering directly over the islands through the weekend. Additional surges of increased low-level moisture coinciding with this upper low have the potential to bring periods of wetter trade wind weather at times into early next week, particularly during the overnight through early morning periods.
Aviation
A surface high pressure cell centered far northeast of the state will continue to bring moderate to breezy east or east-northeast trade winds to the islands through the forecast period. This pattern will allow for scattered showers to affect mainly areas along the windward coasts and slopes. Brief periods of MVFR ceilings and visibility accompany any of the more robust activity.
AIRMET TANGO remains in effect below 7000 feet over and immediately southwest through northwest of mountains due to moderate turbulence.
Marine
High pressure far northeast of the state will produce moderate to locally strong easterly trades through most of the week. The Small Craft Advisory remains in effect for the windier waters and channels from Molokai to the Big Island through Wednesday.
Tiny northwest (320-330 degree) swell will continue to linger along north and west facing exposures over the next few days. In the extended forecast, Typhoon Guchol will become extratropical in the northwest Pacific over the next few days and will send another out of season northwest (300-320 degree) swell to Hawaii by Friday or Saturday.
Surf along south facing shores will remain small throughout the week with a mix of long period background south and southwest (170-220 degree) swells. Surf along east facing shores should see a slight increase on Tuesday as trades strengthen then decrease towards the end of the week as the trades weaken.
HFO Watches/Warnings/Advisories
Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
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